And here are some curved Indian weapons from before the Mughals for your research:
http://en.wikipedia.org/wiki/Khanda_(sword)
http://en.wikipedia.org/wiki/Talwar
Thank you for the links. I've bookmarked both articles, and some of the links they pointed to. Regarding the khanda your source says "Khanda is a double-edged straight sword." The illustration is misleading, because the prominent mounted warrior is using what appears to be a talwar.
And regarding the talwar, I misled you. While it is indeed pre-Mughal, I often use Mughal as an oversimplification for the Mughal Empire, the preceding Sultanates, and the prior incursions by Islamic Central Asians. The Sultanates date from early 13th century; I meant I was looking for info on the period prior to the whole Islamic hegemony in South Asia.
According to your source, and the places it linked to, it looks like the Rajputs began using the talwar in response to the Muslim's choice of weapons (perhaps they changed fighting styles in accord with the theory you proposed). It does seem that the Kushans used a form of the scimitar, and so Indians would have been familiar with that, even if it was not widely adopted at the time.
So it seems like the pattern is early exposure to curved blades but choice to continue use of straight blades like the khanda, then later adoption and improvement to cope with an ardent foe's cutting edge technology.
Thanks for increasing my knowledge of Indian weapons.
It was believed that a curved sword would impact in such a way as to be less inclinded to stick in the victim, and thus being pulled out of the hand.
I read long ago (35 years or so, sorry I don't remember the source) that this was one of the primary reasons for the relative success of the English cavalry vs. the French cavalry at Waterloo. English doctrine favored slashing (using an adaptation of the talwar as a saber, I just found out thanks to you) while the French favored thrusting on the initial attack against cavalry. Consequently the French inflicted more fatal wounds (from which the wounded might take some time to expire), but the wounds inflicted by the English were more immediately debilitating (incapacitating a man, even if he survives and returns to the fight later). Thus the English continued to inflict more damage and repel the French cavalry, even while suffering heavier losses in the long run.
Which just goes to show that exposition provides a more effective argument than assertion.
"And now back to the program already in progress..."